It appears that BMW may have overestimated the U.S. market appeal for high-end versions of the 550i Gran Turismo, and executives now acknowledge that the six-cylinder 535i probably should have been available at launch. It's not unusual for an automaker to launch an all-new model by shipping mostly loaded, top-level versions in order to absorb the maximum number of dollars from early adopters, but sometimes that approach backfires if the market isn't ready for the new vehicle.

Case in point is the 5GT, of which BMW has apparently sold fewer than 1,200 units in the U.S. since the launch of the polarizing people mover late last year. Interestingly, BMW has found that more women than expected have bought the model, while its less-than-stellar fuel consumption has hurt sales in a still-weak U.S. economy. Gran Turismo sales are apparently ahead of projections elsewhere, but those other markets launched with both gasoline and diesel inline-six engine choices.

Given that the 5GT is best suited as a road trip machine, it might make sense for BMW to install the 3.0-liter diesel from the X5 and 335d as an alternative to the twin-turbo V8. So far BMW has not indicated any plans to offer a diesel GT in America, but the less costly 535i GT is still slated to arrive in the Fall.